Optimal inspection/actuator placement for robust dimensional compensation in multistage manufacturing processes

Nowadays, industry is moving toward the implementation of manufacturing systems capable of adapting themselves in real time when changes or deviations in the production line arise. For this purpose, process knowledge should be applied for production performance estimation together with optimal control systems in order to keep the production quality within given specifications. In this chapter, a brief review of a modeling procedure of multistage manufacturing systems, named state-space model, is provided. The definition of the state-space model can then be used for ensuring process quality by the implementation of a feed-forward control strategy. Under this strategy, it is addressed the challenge of where to place the inspection units in order to estimate the state of the manufacturing system and where to place the controllers in order to enhance the process performance. The general procedure to deal with this problem is presented based on the explicit formulation of the predictive control problem subjected to the removal of the actuator and the inspection stations. A two-dimensional (2D) case study from sheet metal working industry is shown to illustrate the methodology.